1. Field
One feature relates to roaming in different communication systems, and more particularly, to a way to select and/or update a roaming sponsor for a mobile device in a visited serving wireless network.
2. Background
In wireless communications, a core wireless network is managed by a core network operator to provide wireless service to subscriber wireless access terminals within the coverage area of the core wireless network. In order to allow the subscriber wireless access terminals to operate in regions outside the core wireless network (e.g., in regions served by other wireless networks), the core network operator may enter into roaming agreements with the operator(s) of those other wireless networks. Typically, a core network operator may enter into roaming agreements with visited network operators for visited wireless networks implementing the same or compatible communication technologies as the core wireless network. This allows subscriber wireless terminals of the core (home) wireless network to easily roam to other (visited) networks while allowing the core wireless network to perform roaming related authentication, mobile terminated services, bill settlement, etc., as the core wireless network and visited wireless network utilize the same or compatible communication protocols. In such typically implementations, the subscriber wireless access terminal may be a single mode terminal (e.g., able to communicate with just a single type of network).
However, despite such roaming agreements with operators of other compatible networks, a subscriber wireless access terminal may find itself in a region not covered by a network having the same or compatible communication protocols as the core wireless network. For instance, competing wireless communication networks often implement different communication standards. In some cases, a wireless access terminal that typically communicates over networks using a first communication standard may enter a region being served by a wireless communication network that operates on a different second communication standard. Thus, a user that normally gets services from a first type of network (e.g., using a first communication standard) at home (e.g., home network) may seek to get services from a second type of network (e.g., using a second communication standard) when the user travels abroad or to a different region. To this end, the user may use a dual-mode access terminal or temporally use another access terminal that supports the second type of communication standard.
In such situations, a dual mode card coupled to or inserted in the wireless access terminal may be configured to permit Code Division Multiple Access (CDMA)-to-Global System for Mobile Communication (GSM) or Wide Code Division Multiple Access (WCDMA) inter-standard roaming. The dual mode card (such as R-UIM (Removable User Identity Module)/SIM (Subscriber Information Module cards)) may be used by the wireless access terminal (e.g., mobile device, mobile equipment, mobile phones, access terminals, etc.) to facilitate roaming between different types of wireless communication networks. In one example, the Removable User Identity Module (R-UIM) is a card developed for CDMA access terminals that can also act as a GSM SIM card for GSM access terminals (either GSM-only or CDMA/GSM dual-mode) and networks, thereby allowing a user to get services from a GSM or WCDMA network in regions where there is no CDMA coverage. In addition to information for the CDMA network, the dual mode card also includes or maintains a GSM directory that provides all GSM network required identifiers and credentials, which points to a roaming sponsor in the GSM network. The roaming sponsor may be a service provider that can facilitate communications over a visited network. For example, the roaming sponsor may be a service provider that has an agreement with the operator of the visited network to use the visited network. The roaming sponsor acts as the proxy between the home service provider and the visited service provider, so that the home service provider doesn't need to negotiate and deal with individual visited service providers that use a different communication standard. The roaming sponsor allows an out-of-network access terminal to obtain communication services via the visited network. Since the roaming sponsor may be changed from time to time, a solution to update the GSM International Mobile Subscriber Identity (IMSI) in a dual mode card directory over-the-air (OTA) is needed. In particular, where multiple roaming sponsors are available in a particular region, it may be advantageous to utilize one roaming sponsor over another.
Therefore, an update mechanism is needed that allows selection of one roaming sponsor over another in the region of a particular visited serving network.